This invention relates to a dispensing system for a liquid, and, more particularly, to dispensing systems such as hand-pumped spray bottles and hand-held spray cans.
Familiar types of liquid dispensing systems employ a dip tube to convey the liquid to be dispensed from the interior of a container to a liquid transfer device, such as a spray nozzle or a hand pump affixed to the container. One of the problems with such liquid dispensing systems is that they will not dispense the liquid unless the dip tube is in contact with the liquid inside the container. As a consequence, the container must be held substantially vertical unless it is completely full of the liquid.
It is highly desirable to be able to dispense the liquid while holding the container at various orientations in addition to the conventional vertical spraying orientation. Such situations include, for example, applying lubricant to the underside of a machine; applying paint to the deck or ceiling of a compartment; applying window cleaning to the bottom section of a glass door; and applying cleaner to the underside of a toilet bowl, as well as many other applications. The standard dip tube approach cannot provide a liquid flow in these situations and other applications where the surface to be treated is not vertical to the spray.
Various approaches have been proposed to solve this problem. In one, as disclosed in U.S. Pat. Nos. 4,322,020 and 3,257,036, the liquid within the container is enclosed in a bladder. This approach is effective and useful for some applications, but the bladder is subject to leaks and is relatively expensive to manufacture and implement. Additionally, extensive modifications are required to the filling apparatus that loads the liquid into the bladder and container, as compared with systems utilizing a dip tube. In a second approach, as disclosed in U.S. Pat. Nos. 4,775,879 and 3,733,013, the dip tube assembly utilizes a gravity-activated valve. Such dip tubes do not allow the dispensing system to be operated at intermediate orientations between the fully upright and the fully inverted.
Accordingly, there is a need for an improved liquid dispensing system that permits dispensing over a full range of orientations. The present invention fulfills this need, and further provides related advantages.